1. Division of Gastroenterology, Department of Medicine, Johns Hopkins Hospital, Baltimore, Maryland, United States
2. Division of Gastroenterology, Department of Medicine, Royal Prince Alfred Hospital, Sydney, Australia
3. Digestive Disease Institute, Department of Gastroenterology and Hepatology, Cleveland Clinic, Cleveland, Ohio, United States
4. Pathology and Laboratory Medicine Institute, Department of Anatomic Pathology, Cleveland Clinic, Cleveland, Ohio, United States